For full CAT control: Use the Arduino to output a control voltage via a DAC (Digital-to-Analog converter) back to the VCO line. You can then tune the M700 from your PC using Ham Radio Deluxe. This is advanced, but the schematics are widely available.

Hm-180 8pin Microphone Speaker Mic For Icom Ic-m700 Ic-m710 Ic-m600

: To allow programming for Banks A and B, which are often locked, W33 (W1033) should be removed. VCO Retuning

The IC-M700 has a rudimentary noise blanker that works poorly on most impulse noise (ignition, power lines). It effectively mutes the receiver rather than clipping the noise pulses.